Touchscreens, such as liquid crystal displays, are well suited for mobile telephones, 25 personal digital assistants, personal computers, and other compact devices. LCD touchscreens are desirable because their layered structure allows a single interface to both display output and receive touch inputs, a structure that reduces their footprint, weight, and cost. A user selecting an icon on a touchscreen surface may feel a vibration, confirming that the icon has been selected. These sensations are generally not pleasing to the touch and often generate annoying audible tones.
Many users enjoy particular tactile feedback, like the feel of a button depression. Unfortunately many touchscreen systems are not able to generate feedback that emulates particular mechanical inputs such as the pressing of a dome button. Moreover, it is infeasible to embed dome and other mechanical buttons in touchscreen systems, depriving the user of particularized tactile feedback.